#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 2e6 + 5;

int n, m;
int c[N];

int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> m;
  ll sum = 0;
  rep(i, 1, m) {
    int a, b;
    cin >> a >> b;
    int x = (a + b) % n;
    c[x]++;
    sum += i - c[x];
  }
  cout << sum;
  return 0;
}